There are people out there who would assume that a woman of average build, 5'6", and 110 lbs is "healthier" than a similar average build woman, same height at 150 lbs. Because they think skinny = healthy.
Statistically, in that instance the 110lb woman is the unhealthy one, as she would be below the normal weight range according to BMI. And low weight individuals have nearly as many health problems as a group as the obese group does.
The 150lb woman may look a bit soft, and is near the top of the normal weight range, but is probably the healthiest.
Culture and media is skewing "weightist" views to favor those with very low body fat, or who are under weight... this is NOT the healthiest segment of our society. And I'd argue that it's not very natural that our preferences are skewed that way either.
That said... I'm not arguing for people to STAY heavy.
But I do understand a bit of the "love thyself" message behind the fat acceptance words.
IMO a heavy person needs a good deal of self love in order to make the changes necessary to stick to dietary and lifestyle changes long term, which is what it takes to lose weight and keep it off.
Sometimes fat loss is SLOW and difficult, and loving yourself AS YOU ARE makes it easier to see the positive no matter how little the increments are.
Self loathing, or only loving the idea of a smaller you, leads to crash and burn cycles of loss and gain.(Or unhealthy levels of struggle and obsession without results... sound familiar Choco? I think I've read that post from even YOU.)
For many obese people this leads to eventually giving up completely. Not healthy at all...